1. This invention relates to a three dimensional color display and, more specifically, to such a system utilizing plural modulated lasers projecting different colors through a fiber optic system.
2. Brief Description of the Prior Art
It has been known in the prior art to modulate or scan a beam, such as a laser beam and then to project the scanned beam onto a screen. Examples of such systems are set forth in Baker Patent Nos. 3,471,641 and 3,549,800.
It has also been long desired to provide a three dimensional display. Prior art systems for creating such a display have involved moving a flat plate mirror or flexing a plastic mirror to reflect a CRT image to create a volume display. Similar techniques have employed a Mylar membrane stretched over a metal ring and silvered on the from surface, such mirror being vibrated to reflect the information displayed on the CRT in synchronism with the mirror motion. Such techniques and techniques for converting a cathode ray tube two dimensional display into a three dimensional image are discussed in the article "Terminal Puts 3-Dimensional Graphics on Solid Ground", by Harry S. Stover, Electronics, July 28, 1961.
Prior art three dimensional display techniqes were limited because of their use with CRT screens in that the produced image may be viewed only from selected angles. Moreover, such prior art systems have generally not been able to produce real time images and have been limited in the possible vibration frequencies of the screens. Furthermore, the use of vibrating mirrors has created difficulties due to the relatively large mass of the mirrors which prevent substantial deflections. For example, such prior art systems have generally been capable of providing a mirror displacement of about 0.4 millimeters.
A need thus arose for a simple and economical three dimensional display system that could produce substantial displacement at a variety of frequencies in order to provide three dimensional images which can be viewed from all angles. A system which solved this problem is known wherein the three dimensional display includes a laser which directs a beam of light toward a mirror, the mirror being moved in an X-Y plane by piezoelectric transducers. The reflected light beam is directed to a vibrating screen which is moved by a piezoelectric transducer to form a three dimensional image. This system, while providing the desired result, is limited as to the size of the image displayed since the screen and image size are determined by the size of the piezoelectric transducer. Also, this system is affected by G forces, thereby presenting problems where such forces exist, such as in aircraft.
The above problems have been minimized in accordance with the system described in the continuation application of Garcia et al., Serial No. 231,638, filed Aug. 8, 1988 and assigned to the assignee of the subject application wherein a single laser and modulation system provide a light beam which is directed onto an x-y scanner, the latter providing a two dimensional image on a rotating screen. The rotating screen is positioned so that points on the image are constantly moving along an axis normal to the image plane to provide a three dimensional image. The above noted prior art is incorporated herein by reference. This copending application is incorporated herein by reference. In addition, U.S. Pat. Nos. 1,794,103, 3,682,553 and 3,970,361 set forth typical prior art displays of the above noted type.
The above noted prior art still is unable to adequately provide three dimensional color images wherein the colors can be continually varied on-line.